How do different nitrogen application levels and irrigation practices impact biological nitrogen fixation and its distribution in paddy system?

Background and aimsBiological nitrogen fixation (BNF) in paddy systems is impacted by application levels irrigation strategies, but the extent to which these factors influence BNF its distribution soil rice largely unclear. This study investigates this influence.MethodsAn airtight, transparent growth chamber based 15N-labelling system was used investigate how different (0, 125, 187.5 250 kg N ha?1) strategies (flooding or intermittent irrigation) impact amount of rice.ResultsNitrogen at 125–250 ha?1 reduced 81–86%. The inhibition effect on a depth 1–15 cm greater than that 0–1 cm. Relative continuous flooding irrigation, enhanced promoted transfer fixed from 0-1 layer rice, it did not change total BNF.ConclusionsThis indicated supplied little for production high levels, could promote utilization biologically nitrogen.